<!DOCTYPE html>
<html>
<head>
<style>
 #header{
 		background:yellow;
 		width:100%;
 		height:50px;
 		clear:center;
 }
 
 #nav{
 		background:red;
 		width:30%;
 		height:100px;
 		float:left;
 }
 #content{
 		background:blue;
 		width:70%;
 		height:100px;
 		float:right;
 
 }
#footer{
		background:aqua;
		width:100%;
		height:50px;
		clear:both;
}

</style>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<div id ="header">heaer</div>
<div id ="nav">nav</div>
<div id="content">content</div>
<div id="footer">footer</div>



</html>